Radiography (or roentgenography) is the method of taking a picture with the help of X-rays, and the terms radiograph or simply X-ray are sometimes used for the resulting picture. Radiogram is the correct name for an image taken by radiography.

RADIOLOGIST

A physician who uses x-rays or other imaging procedures for diagnosis and treatment.

Radius

Latin = spoke of a wheel, which rotates around the hub; hence, the lateral bone of the forearm, which rotates (though around an almost vertical axis); adjective - radial.

Radix

Latin = root.

Ramify

Latin ramus = a branch; and facere = to make; hence, to branch.

Ramus

Latin = branch; hence, a branch of a nerve.

RANDOMIZED TRIAL

A clinical trial arranged to produce a chance distribution of participants into different arms (e.g., experimental treatment, standard treatment, or placebo). Randomization is done to minimize bias.

Randomized, Double-blind, Placebo-controlled, Mult

A clinical trial in which patients have been randomly assigned to receive either the study drug or the alternative treatment under study. Neither the patient nor the doctor conducting the study knows which treatment is being given; the alternative to the study drug is a placebo; and the study is conducted at several centers.

Randomized, Double-blind, Placebo-controlled, Mult

A clinical trial in which patients have been randomly assigned to receive either the study drug or the alternative treatment under study. Neither the patient nor the doctor conducting the study knows which treatment is being given; the alternative to the study drug is a placebo; and the study is conducted at several centers.

Range Of Motion

The extent to which a joint is able to go through all of its normal movements. Range-ofmotion exercises help increase or maintain flexibility and movement in muscles, tendons, ligaments, and joints.

Raphe

Greek a seam; hence, the line of junction of the edges of 2 muscles or areas of skin.

RAPID VIROLOGICAL RESPONSE (RVR)

The probability of achieving a sustained virological response early in treatment based on a decline in HCV RNA (viral load). The generally accepted timeframe is 4 weeks after starting treatment.

Temporary interruption of blood flow to the extremities (fingers, toes, tip of nose and ears), often associated with exposure to cold temperatures.

RBC

Red blood cell. See erythrocyte.

REACTIVATION

The return of a previously latent (inactive) infection to an active, pathogenic state.

Reactive Arthritis

Arthritis resulting from infection elsewhere in the body; i.e. there is no infection in the joint. The most common type is HLA B27-related and may follow certain types of bowel or genitourinary infection.

REACTIVE ARTHRITIS (REITER'S SYNDROME)

An arthritic disorder, often linked to conjunctivitis, that appears to be associated with viral infections.

REBETOL

Schering’s brand of ribavirin. see ribavirin.

REBETRON

A bundled kit for HCV treatment that packages together Intron-A brand interferon and ribavirin.

REBOUND

An increase in viral load following a previous decrease.

RECEPTOR

A specific binding site on a cell's surface or in its interior. When chemical messengers or drugs bind to receptors, various cellular functions are activated or inhibited. Viruses must bind receptors in order to enter cells.

Recess

Latin recessus = a secluded area or pocket; hence, a small cavity set apart from a main cavity.

RECOMBINANT

Produced by genetic engineering.

RECONSTITUTION

Mixing a substance (e.g., Peg-Intron brand pegylated interferon) with water to return it to a usable form.

Rectum

Adjective, Latin rectus = straight. (The rectum was named in animals where it is straight - which it is not in Man).

Rectus

Latin rectus = straight.

RECURRENT

Returning or occurring repeatedly.

RED BLOOD CELL

See erythrocyte.

Reference Range

The reference ranges have been compiled on basis of a population of 1000 healthy persons and are separated for gender.

Reflex

An involuntary response - muscular or secretory - to a stimulus mediated by the central nervous system.

REFLEXOLOGY

An alternative healing technique that involves putting pressure on various zones of the body.

The removal of bone tissue — both protein and minerals — by osteoclasts (see Osteoporosis).

RESPONDER-RELAPSER

A person who initially responds well to a treatment, but then experiences a relapse. In chronic HCV infection, this refers to a person who initially has a positive response to treatment (e.g., normal ALT, undetectable HCV RNA), but does not sustain this response once treatment is stopped.

RESPONSE TO TREATMENT

See treatment response.

Restenosis

Renarrowing of a blood vessel that has been widened (with or without stents) during angioplasty (see Cardiovascular Health).

Latin retro = backwards, and flexion = bent; hence, the position of being bent backwards, applied to the angulation of the body of the uterus on the cervix.

RETROSPECTIVE STUDY

A study based on medical records, looking backward in time at events that happened in the past. Contrast with prospective study.

Retroversion

Latin retro = backwards, and version = turned; hence, the position of being turned backwards, applied to the angulation of the cervix uteri on the vagina.

RETROVIRUS

A class of viruses that have their genetic material in the form of RNA and use the reverse transcriptase enzyme to transcribe their RNA into DNA within the host cell.

Rheumatic Disease

Any one of over 100 disorders that cause inflammation in connective tissues (see Arthritis).

Rheumatic Fever

A form of reactive arthritis triggered by streptococcal sore throat. Its features include very painful joint inflammation (arthritis). It is now uncommon in developed countries but still occurs commonly in other parts of the world. It can cause inflammation and scarring of heart valvos (rheumatic heart disease).

Rheumatism

Pain and stiffness of soft tissues in and around joints (see Arthritis).

Rheumatoid Arthritis

A chronic systemic disease that causes inflammatory changes in the synovium, or joint lining, that result in pain, stiffness, swelling, and ultimately loss of function and deformities of the affected joints due to destruction of the cartilage and adjacent bone. The disease can also affect other parts of the body. In the past it was also called chronic polyarthritis. It is more common in women than men, and at least 70% of patients show a positive blood test for rheumatoid factor.

RHEUMATOID ARTHRITIS (RA)

An autoimmune condition characterized by joint inflammation and destruction of connective tissue; other organs, including the heart, lungs, kidneys, and skin, may also be affected.

RHEUMATOID FACTOR

A type of antibody (IgM) that reacts to abnormal IgG antibodies produced by people with autoimmune conditions such as rheumatoid arthritis.

Rheumatologist

A doctor (board-certified internist or pediatrician) who has had specialized training in diagnosing and treating disorders that affect the joints, muscles, tendons, ligaments, connective tissue, and bones.